Apparatus for producing series wound heaters for plural cathode electron tubes



March 9, 1965 J. PAULL 3,172,433 APPARATUS FOR PRODUCING SERIES WOUND HEATERS FCR PLURAL CATHODE ELECTRON TUBES Filed Dec. 22, 1961 4 Sheets-Sheet 1 44 INVENTOR.

Jack Pa all March 9, 1965 J, PAULL APPARATUS FOR PRODUCING SERIES WOUNDHEA-TERS FOR PLURAL CATHODE ELECTRON TUBES 4 Sheets-Sheet 2 Filed Dec. 22, 1961 INVENTOR. 20k Pa 11]] 4/4 TTOF/VEY March 9, 1965 J. PAULL 3,172,433

APPARATUS FOR PRODUCING SERIES WOUND HEATERS FOR PLURAL CATHODE ELECTRON TUBES Filed Dec. 22, 1961 4 sheets-sneer:

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Jack Paull BY W lrrflIA/E/ March 9, 1965 Filed Dec. 22, 1961 J. PAULL APPARATUS FOR PRODUCING SERIES WOUND HEATERS FOR PLURAL CATHODE ELECTRON TUBES 4 Sheets-Sheet 4 INVENTOR.

Jack Pa all United States Patent Ofi ice 3,172,433 Patented Mar. 9, 1965 3,172,433 APPARATUS FOR PRODUCING SERIES WOUND HEATERS FDR PLURAL CATHODE ELECTRON TUBES Jack Paul], Grange, N.J., assignor to Radio Corporation of America, a corporation of Delaware Filed Dec. 22, 1961, Ser. No. 161,692 19 Claims. (Cl. Nth-71.5)

This invention relates to an apparatus for producing continuous, one piece, gap-type heaters for electron tubes having a plurality of cathodes, and more particularly, to improvements in gap-type heater spade winding machines.

Many plural-purpose electron tubes contain a plurality of cathodes, each comprising a cathode sleeve and each cathode being heated by a heater wire comprising an insulated resistance wire mounted within the cathode sleeve. The resistance wire from which the heaters are made is supplied in long insulated integral lengths, and spaced portions thereof are bent into required form for inserting into the respective cathodes of the plural-purpose electron tubes and then the bent portions are cut off to proper length.

A present method of making series heaters of the socalled gap-type for plural-purpose electron tubes is to make separate heaters, as by winding them individually on an automatic heater winding machine or spade winder, and then welding a connector between an end of one heater wire and an end of another heater wire.

One form of an automatic spade winder used to produce separate individual heaters comprises a rotating winding head from one end of which two spaced parallel blades extend and on which a wire gripping means is provided. The end of the heater wire is held in the gripping means, and as the head, mounted on a power-driven shaft, rotates, the heater wire is fed so as to wind wire on the blades in a helical manner. After a predetermined number of turns have been wound, automatic controls stop rotation of the winding head, and the wire is cut, the insulation being simultaneously broken off and stripped from the ends of the wire. The blades at least one of which is pivoted are then moved towards each other to a collapsed position to permit an operator to remove the completed heater from the blades. The heater, so produced, is a complete heater for a single cathode. The use of such a winder to produce series heaters for plural cathode tube, therefore, involves, besides the production of individual heaters, the extra steps of welding connectors between the ends of the individual heaters.

A further prior art automatic spade winder has been developed for winding a pair of series heaters in which one heater is limited to one turn, while the other heater of the pair may have any predetermined number of turns. A heater produced on such an automatic spade winder is useful only where one turn only of heater wire will provide sufiicient heat to raise a cathode to its electron emitting temperature. Many electron tubes have plural cathodes each of which requires more than one turn of heater wire to raise them to operating temperature. Present known automatic spade winders are not suitable for supplying integral series heaters for such an electron tube.

This last mentioned prior art automatic spade winder for winding a plurality of heaters in series of which one comprises but one turn, is provided with a short, third blade in addition to the two blades of the single heater winding device. An initial part of the heater wire is wound for one turn only over the three blades, and a further part of the heater wire is wound for any predetermined number of turns over only the two of the three blades. The first turn of the heater winding therefore comprises, in effect, two legs of a triangle and a base therefor. The two legs of the triangle comprise the heater for a cathode and the base provides an integral connection from the one turn heater to the heater that is wound on two blades only.

Another apparatus for making series heaters involves a drum having longitudinally arranged ribs on the periphery thereof. In using this apparatus, heater wire is wound around the drum in contact with the ribs. The heater wire on the drum is bent inwardly at the location of the ribs. Then the heater wire is out OK the drum to predetermined lengths, and the cut-01f portion of heater wire is formed into integral series heaters by further manual bending thereof. This method of making series heaters involves a substantial amount of careful manual labor, and is slow and expensive.

It is therefore an object of this invention to provide an apparatus for winding continuous gap-type heaters for plural-cathode electron tubes in which each cathode requires more than one turn of heater wire.

It is a further object of this invention to provide an apparatus for automatically winding continuous gap-type heaters for plural cathode tubes, each heater comprising a plurality of turns, which apparatus does not require the attendance of highly skilled workers.

In accordance with this invention, the winding head of the automatic spade winding machine is provided with three spaced winding blades, one of said winding blades normally being retracted to a point where no heater wire will be wound thereon. An initial portion of heater wire is wound in a helical manner on two of the blades beyond the end of the retracted blade. After a predetermined number of turns have been wound on the said two blades, the third blade is extended parallel to and laterally of the first two blades, to the point where its end extends beyond the already wound turns but only far enough so that one turn only of helically wound heater wire is wound on all three blades. This is done while the helical winding operation continues. A subsequent portion of heater wire is wound in a helical manner around the two blades only, and beyond the end of the third blade. Therefore, the two windings on the two blades only comprise the two heaters and the portion of the single turn wound on the three blades comprises a connection between the two heaters.

A fourth winding blade, laterally spaced from and parallel to the first two winding blades may be provided. The fourth blade is short, and is fixed in its position relative to any one of the first two winding blades. The heater wire is wound in a helical manner, an initial single turn of heater wire being wound on the first, second and fourth blades. A subsequent portion of the heater wire is wound helically around the portions of the first two blades which extend beyond the fourth blade, as described above. After a predetermined number of turns have been wound on the first two blades, the third blade is extended parallel to the first two blades, as described above, to the point where one turn only is wound on the first, second and third blades, and

finally, a plurality'of turns are wound on the first two blades, beyond the end of the extended third blade. The

resultant winding comprises a series of heaters, one heater comprises only one turn and two heaters each comprising any predetermined number of turns, either equal to each other in number or different in number.

In either embodiment of this invention, that is, the embodiment using three blades or the embodiment using four blades, other means are provided for moving the blades closer together after the winding is completed than during the winding operation, so that the completed heater may be stripped from the blades on which the heater is wound.

The invention is more fully explained in the following description, taken with the accompanying drawings, in which:

FIG. 1 illustrates a heater made by the apparatus incorporating this invention;

FIG. 2 is a side elevation of a spade winder made according to this invention;

FIG. 3 is a sectional view on line 3-3 of FIG. 2;

FIG. 4 is anend view of the winding head of the wind er of FIG. 2 showing the mechanism for operating the third blade;

FIG. 1 shows a gap-type heater If) that can be wound by apparatus incorporating this invention. As shownin FIG. 1, the heater wire, which comprises a resistance wire covered with insulation, isbent into the form shown,

by the apparatus hereof. At the sharply bent portions 12, the insulation 14 may break off, since the insulation "14 is relatively brittle. At the less sharply bent portions '16, the insulation 14 may crack but often remains. At

the terminal legs 18. of the heater 10, the insulation is broken away after the wire is wound and just before it is severed; It will be noted that FIG. 1 shows three heaters 22, and 24 wound in series, the first heater 20 thereof comprisingone turn only and the second and third heaters '22 and 24 comprising a predetermined plurality of turns, the heaters being joined by integral connecting portions 26 and 28. As will be explained below, the first one turn heater 20 may be omitted in which casefthefree end of the second heater 22 is extended to form a leg or terminal portion.

H eater winding device-intr0ducti0n The apparatus for making a heater such as that shown in FIG. 1 is shown in FIG. 2. A heater winding head 32 is mounted at one end of a hollow power-driven shaft '34. The shaft 34 is rotatably supported on and projects in a horizontal direction from the supporting frame 36).

The opposite end of the shaft 34 is connected to an electrically operated magnetic clutch 36 which is coupled to the motor and speed'reduction device 38. Whenthe clutch 36 is energized the shaft '34 is coupled with the continuously operated motor.

A wire feeding means 40 is provided for feeding heater Wire to the winding head 32. This wire feeding which is shown), one of these guide wheels being mount ed to turn only in feeding direction. The heater wire is drawn between guide wheels 44 and through a wire guide 46 comprising a part of the wire feeding means, While feeding wire to the winding head 32, the feeding means 40 is moved to the right, as viewed in FIG. 2. To provide this motionof the wire guide and feeding means 40, the shaft 42 ,on which the feeding means 40 is supported, is slidably'but not rotatably mounted in frame 30. The shaft 42. is pushed to the right by cam 48 upon clockwise rotation thereof. A biasing spring 50 connected between a pin 52 mounted on frame 30 and a stop 54 mounted on shaft 42 urges shaft 42 against the cam 48. The cam 48 is rotated clockwise by gear mechanism 56 which is driven by shaft 34 by means of gears 58; Thus, as shaft 34; rotates cam 48, the shaft 42 gradually moves to the right until the end of the shaft 42 rides off the highpart of the cam 48. The shaft 42 is then pulled back quickly by spring 50.

Cam for tilting motion of winding blades As noted above, the blades on the winding head are parallel, as shown in FIG. 8, while the heater is being blade tilting means, more fully described below, includes a cam 661(FIG. 7 or 8) slidably mounted in and concentric with hollow shaft34. The cam'6t) has a rounded nose which extends into the winding head 32, to be described in detail. The. cam69. has two extreme positions as shown respectively in FIGS. 7 and 8. The cam 6% is moved between its two extreme positions by air cylinder 62, FIG. 2, vertically mounted on frame 30. The piston rod 64 of the air cylinder 62 is connected to a bell crank 66 which is pivoted on frame 30 by means of bracket 68. Upon admissionof air to the cylinder 62, the bell crank 66. is rotated clockwise asviewed in FIG. 2. A tension spring 76, stretched between bell crank 66-and frame member 72, resiliently. urges the bell crank 66 counterclockwise. As shown vin FIGS. 2 and 3, a slidable collar 74 surrounds hollow shaft 34 and a pin 7 6 extends through the collar .74 and'into cam tithrough a slot 78 in hollow shaft 34 A pin 89 extends through the end of hell crank 66 into a groove 82inthe collar 74. Therefore, upon admissioncf air under pressure into air cylinder 62, the cam 60 will be moved to the right andupon exhaustion of air from'cylinder 62, cam 6% will be moved to the left by contraction of spring 70. The motion of cam 66 to the'right causes bladesIEh, I32'and 142 to'assume a position parallel'to blade 114x Motion' of earn 6% to the left permits tiltingv of blades 130, I32 and 142 as will be' explained.

Cut and CltZCk-Ofi mechanism When a heater has been wound,'the ends thereofa-re cut and the brittle insulation thereon is broken 01f. This is accomplished by the cut and crack-oif'mechanism 84 shown'in FIG. 2. This cut and crack-off mechanism 84 is of a known type and it is described'only as it appears necessary. This mechanism'cornprises two rotatable arms 86, each mounted on frame 36 by means of rotary shafts 88' towhich the arms are attached. These arms 86 carry at the top thereof cooperating wire cutting and crack-off heads 99." Since one arm is behind the other, only one arm 86 and one shaft 88 and one head 90 is visible in 2. Upon turning the two arms 86 towards each 'other, the cooperating wire cutting and crack-off heads 90 strike each other below the blades and above the wire gripper (to be described). on the winding head 32. The

cutter portion of the cut-off heads 9% cut the ends of the heater Wire wound on the blades below the. four blades and above a wire retainingbuttonl'id to be described, on the winding head v32, the cra'ckbif portion of the heads ht) breaking the brittle insulation off the heater wire just above the cut-off ends thereof. .The means for causing the two arms 86 to turn towards each other comprises an air cylinder 92 mounted below frame 30. The piston rod 94 of the air cylinder 92 is fixed to two connecting rods 96 (only one being shown) pivotally attached to levers 98 (only one being shown), which are fixed to the bottom ends of shafts 88. Upon admission of air to the cylinder 92 in a direction to push the piston rod 94 to the right, as viewed in FIG. 2, the crack-off arms 86 are rotated towards each other whereby the crack-off heads strike each other with the heater wire therebetween, cutting the heater wire and cracking off the insulation as noted above.

Winding head The winding head is shown in FIGS. 2 and 4 to 8. The winding head comprises a housing 99 (FIG. 7 or 8). One end of housing 99 comprises a block 109. A bore 182 extends into the block 100 of a size to fit the hollow shaft 34 on which the block is mounted. The bore continues with a smaller diameter 104 to receive the above-mentioned cam 60. A plate 196 (FIG. 4) is an integral portion of block 1%. Walls 108, and 112 (FIGS. 4, 6, 7 and 8) integral with plate 106, extend along three sides thereof. A cover plate 116, FIGS. 5 and 6, is fixed to the walls 168, 116 and 112 to complete the housing 99.

The blades are mounted in the housing 99. The retractable blade 142 is shown retracted in FIG. 8 and extended in FIGS. 6 and 7. Also in FIG. 7, the second, third and fourth blades, blades 130, 142 and 132 respectively are shown tilted. A fixed blade 114 (FIGS. 4-, 5, 7 and 8) is clamped to plate 106 and extends from winding head 32 in a direction away from bore 192 and parallel to the axis thereof.

A pin 118 (FIGS. 6, 7 and 8) extends through holes in integral plate 106 and in the cover plate 116. Wide slots 120 and 122 are provided in the integral plate 106 and in the cover plate 116, respectively, to the right (as viewed in FIG. 6) of pin 118. A tiltable blade support 124 is pivotally mounted on pin 118. This blade support 124 includes a longitudinally directed slot 126 which is narrower than slots 120 and 122. Slot 126 is to the right, as viewed in FIG. 6, of and in line with pin 118 and is of a size to slidably fit a pin 128 to be described. A flat thin blade 139 and a short blade 132 are fixed by clamp 134 to one side of a reduced portion 136 of the blade support 124. The short blade 132 is triangular in transverse section, having -a rectangular shank, and is so mounted that the triangular blade 132 is parallel to but spaced from the tiltable fiat blade by a predetermined distance equal to the desired length of the heater connector 26 of FIG. 1. Upon tilting of blade support 124 about pin 118, blades 130 and 132 tilt with it as shown in FIG. 7.

A slidable blade holder 138 is provided in head 32. A slot 149 in the slidable blade holder 138 is of a size to slidably receive pin 118. The pin 128 extends through slidable blade holder 138, and through the slot 126 in the tiltable blade holder 124. Pin 128 also extends loosely through slots 120 and 122 in plate 106 and cover plate 116. A triangular slidable blade 142 having a rectangular shank is fixed to slidable blade holder 138 by cap screws 144 (FIG. 6) extending through the rectangular shank of slidable blade 142. Therefore, upon tilting of tiltable blade support 124, slidable blade holder 138 is constrained to tilt with it, however, slidable blade holder 138 may slide on tiltable blade holder 124. The slidable blade 142 and the tiltable blade 13% are a distance apart equal to the length of the heater connector 28 of FIG. 1.

The means 146 for holding the sliding blade 142 in retracted position comprises the pin 128 extending through the slidable blade holder 138 and a further pin 156, to the rear of and parallel to it (FIGS. 4 and 6) extending through the winding head 32. Tension springs 152 are stretched between the respective ends of the pins 128 and 150, yieldably holding the sliding blade holder 138 in its retracted position. A mechanism 154 (FIGS. 4 and 5) is provided for moving the slidable blade holder 138 to its extended position. This mechanism 154 comprises a pair of slides 156 slidably held on plate 106 and on cover plate 116 respectively by slide covers 158. The pin 128 extends through the slides 156 and through wide slots 160 in slide covers 158 (FIG. 6). The ends 162 of slides 156 are oifset and rollers 164 are mounted on the offset portions of slides 158 to contact a cam means 166 (shown in FIGS. 2, 4 and 5 but omitted from FIG. 6) to slide the slidable blade 142 to its extended position, as will be explained.

The means 148 for tilting the tiltable blades 130, 132 and 142 is best shown in FIG. 4, 7 and 8. This means comprises tension spring 168 stretched between the pin 171 fixed to plate 106 and a lug 169 fixed to tiltable blade holder 124. Upon clockwise rotation of tiltable blade holder 124, spring 168 is put in tension as the three tiltable blades 130, 132 and 142 are moved to a position parallel to the fixed blade 114. Upon movement of cam 69 from the position shown in FIG. 7 to the right to the position shown in FIG. 8, in the manner explained above, the cam 68 contacts an adjacent surface of tiltable blade holder 124. This contact of cam 60 on tiltable blade holder 124 rotates the blades 130, 132 and 134 about pin 118 from the position shown in FIG. 7 to the position shown in FIG. 8. In this figure, blade 142 is also retracted.

The winding head 34 has attached to its lower side a wire gripping clamp 179 as shown in FIGS. 5, 7 and 8. The clamp 178 projects outwardly from the winding head 32 parallel to the blade 114 for a distance just short of the end of the short blade 132 and beyond the end of the slidable blade 142 when the slidable blade 142 is in its retracted position. The clamp 176 comprises a tubular bearing 172 fixed in Wall portion 112 of the housing 99, the bearing 172 extending parallel to the fixed blade 114. The tubular bearing 172 has an enlarged exposed end 174. A pin 176, having a head 178, is slidably mounted in housing 99 and extends through bearing 172 and through the wall 188 of housing 99. A collar 179 and a retainer ring 189 are fixed to pin 176. Two washers 182 and 183 are slidably mounted on pin 176 betwen collar 179 and retainer ring 188, and a compression spring 184 surrounds pin 176 between the slidable washers 182 and 183. A bifurcated depending yoke 186 which is integral with the tiltable blade holder 124, embraces pin 176 between collar 179 and slidable washer 183. Thereby, as shown in FIG. 7, when the tiltable blade holder 124 is tilted with respect to fixed blade 114, the yoke 186 pushes on collar 179 and pushes pin 176 to the point where the head 178 of the pin 176 is spaced from the enlarged portion 174 of the bearing 172. The wire clamp is then open. However, when the tiltable blade holder 124 is held parallel to the fixed blade, as shown in FIG. 8, the yoke 186 acting through washers 183 and 182, spring 184 and retainer ring 189, resiliently holds head 178 against enlarged portion 174 to keep the clamp 170 closed and in clamping position.

The apparatus 154 for causing sliding of the slidable blade 142 is best illustrated in FIGS. 2, 4, 5 and 6. As noted above, slides 156 are resiliently urged to the left as viewed in FIGS. 2 and 6, holding the slidable blade 142 in retracted position.

Located to the left of the winding head 32, is a pair of coaxially mounted cylindrical cams 188 and 190 which function, as will be described, to move slides 156 and to extend slidable blade 142. These earns 188 and 199 are a pair of coaxially mounted cylinders of the same diameter each having ratchet-like teeth 192 at registering ends thereof, the teeth 192 being of mating shape and being in contact. Cam 198 is fixed to the winding machine frame 36 by means of an anchor plate 194 and cam 188 is rotatable about an axis coincident with the axis of the shaft 34. A concentrically mounted cylindrical member 1%, shown in FIG. 4 and 5, extends outwardly from the pushing rollers 164 and therefore slides 156 and sliding blade 142 to its extended position against the biasing action of spring 152. When rotatable cam 188 has been rotated to the point where theflat tips 19% of the teeth 192 of the two cams 188 and 19% are in contact, a position of rest is reached since there is no rotary component of the axial force provided by tension springs 152 on cam members 188 and 190 in this position of the teeth thereof. Another position of rest of cams 188 and 1% is when their teeth 192 are fully mated. Therefore, the slidable blade 142 has two positions of rest, one when it is fully extended, the cams 188 and 190 having the flat teeth portions 198 in contact as shown in FIG. 5 and the other position of rest when the blade 142 is fully retracted the cams being fully nested, as in the position shown in FIG. 2.

Means are provided for rotating the cam 1% with respect to cam 1-90, this means comprising an air cylinder 200 (FIGS. 2 and 4), pivotally mounted on support plate 195, the piston rod 2tl2 of the air cylinder 2% being pivotally. fixed to cam member 133 at 204 (FIG, 4). Upon admission of air under pressure to air cylinder 2%, rotary cam 1558 is rotated clockwise (as viewed in FIG. 4) to the position shown in FIG. 5 where the flat tips 198 of the teeth 192 of the cams 188 and 19% are in contact. After the completion of the winding of the heater it and after it has been removed from the several blades, the blades being moved to the position shown in FIG. 7 to make removal possible, air is released from the bottom of air cylinder 2&0 and air pressure is applied to the top thereof rotating cam 138 counter-clockwise, whereby the cams 18S and 19% resume the relative position shown in FIG. 2.

Timing The timing of the various actions is controlled by the cam switches shown in FIG. 9. The cams may be driven by the continually operating motor at 38 of FIG. 2. Cam 2% causes closing, of the switch 2% which energizes magnetic clutch 36. Cam 2143 causes closing of switch 212 which energizes the solenoid 214 which in turn causes admission of air under pressure to crack olf cylinder 92.. Similarly, cam 216 closes switch 218 to energize solenoid 22% to cause admission of air to ratchet cam air cylinder 2G0 and cam 222 closes the switch 224 to energize solenoid 226 to cause admission of air to sliding cam cylinder 62.

Operation Operation of this machine is as follows, it being noted that if desired, the fourth or short blade 132 may be omitted, in which case the first hairpin heater 2% will not be formed. While the series heater lll produced will be changed to this extent, no change in theoperating cycle of this machine will result from the omission of this short blade 132, the sliding blade 142 operating in combination with the other blades 114 and 130, with or without the short blade 132.

At the beginning of the cycle, cam 48 (FIG. 2) is in position .to permit spring 50 to pull shaft 42 to its extreme left-hand position whereby'the wire feeder -40 is atits extreme left position. The head 32 is in a vertical position with the fixed blade 114 at the top and the wire clamp 17% at the bottom. Bell crank 66 is at its extreme counterclockwise position, pulling' sliding cam 60, FIG. 7, to the left and allowing spring 168 to pivot pivoted blade holder 124 counter-clockwise. The extensible blade 142 is fullyextended. In this position, the three blades 136, 132 and 142, mounted on pivoted blade holder 124 are tilted upward towards the fixed blade 114- whereby a previously made heater 16 'is held so loosely onthe blades 114, 139, 132 and 142 that the operator can easily remove the completed heater Iii. Also in this position of the tilted bladej holder 124, the lower or cam portion 186 thereof pushes rod 176 to the right, opening the wire clamp 170. The position of the wire feeder 40 is such and the length or" the wire fed thereby is such that the end of the wire rests in the open clamp 17d.

The timing cams, as shown in FIG. 9, are in a portion of their cycle where a heater is almost completed. At the beginning of the cycle however,-the timing cams are in such position that switch 2% is the only one closed, switches 223, 212 and 224 being open. 7

To commence the cycle,.the timing cams rotate from their position at the beginning of the cycle and the switch 218, in opening, causes retraction of slidable blade142. Further rotation of the timing cams causes admission of air to the cylinder 62 whereby the cam 64? is caused to slide to the right, pivoting the tiltable blade holder 124 to its parallel position and providing pressure on spring 134 (FIG. 8) to close wire-clamp 17% to grip the heater Wire. Upon further rotation of the timing cams, the magnetic clutch 36 (FIG. 2) is energized and the shaft 34, and therefore the winding head 32, starts to rotate causing winding of heater wire on the projecting blades. Rotation of shaft 3 also causes rotation of cam 48 to cause wire feeder i-d'to move to the right to cause wire to be fed helically to the rotating head 32. During this part of the cycle, the sliding blade 142 is held in its retracted position, the end thereof now being to the left of the wire clamp 17%. If the short blade 132 is used, the wire is wound over the three blades 13%, 132 and 114 for one turn-and then, after the first turn, due to the motion of the wire feeder 449 to the right, the wire is fed only on the two blades 13% and 114 beyond the end of the short blade 132. In the absence of the short blade 132, wire is wound only on the two blades 1-30 and 114 up to this point in the. operation ofthis device.

After a predetermined number of turns of the winding head, the continually turning timing cam 216' causes admission of air to the bottom of ratchet air cylinder 2% and the slidable blade 1.42 shoots out, during a portion of a turn of the head 32, to apoint where a single turn only of heater wire is wound over the fixedblade 114, the tiltable blade 13b and the end of the extensible blade 142. Due to the continued motion of feeder 40, further turns of heater wire'is wound only over the fixed blade 114 and the tiltable blade 1343. Upon further rotation of the timing earns, the magnetic clutch 36 is de-energized at such a tirne whenthe head 32 is vert-icalandtheclamp 176i is down, as shown in FIG. 5. The timing cams continue to rotate and switch 212 causes air to be admitted to the crack-off air cylinder 92, causing the crack-off means '84 tocut the heater wire at the end of series heater 1t and to crack oil". the insulation at the cut ends of the heater. Upon further rotation of timing cams, air is released from cylinder 62 and cam fill is retracted by spring 70, allowing spring 158 to pivot the tiltable blades counter-clockwise to the positionshown in 1 16. 7. The extensible blade 142, at this-time, is in'its extended position. The heater It is held loosely on the blades to give the operator the opportunity to remove the series heater. The timing cams continue to rotate andthe switch 218 is allowed to open, exhausting air from the bottom of ratchet cam cylinder 2% and applying compressed air to the top thereof, whereby the extensible blade 142 is retracted-and the cycle is completed. In all, the extensible blade is held vin extended position from the time that a single turn is put thereon until the completed heater is removed from the assembly of blades.

As shown in FIGS. '5, 7 and 8, the two long blades 114 and 130 have oppositely directed serrated edges. The purpose of these serrations will become clear upon reference to FIG. 1. It will be noted that at the sharp bends 12 in the heater 10, insulation is broken off the heater wire and if the blades comprised no serrations, the sharply bent portions thereof and therefore the bare parts of the wound heater would all be at the same elevation, resulting in the likelihood of a short circuit of one or more turns of the heater due to the bare portions thereof coming into contact. However, since the heater wire is wound over blades having serrations along opposite edges thereof, the heater will be bent sharply at different elevations as shown in FIG. 1, avoiding the likelihood of a short circuit.

What is claimed is:

l. A winding head for winding a gap-type heater comprising a housing, means for rotating said housing, a plurality of winding blades mounted on said housing, one of said blades being mounted on said housing for tilting from a Winding position to a winding release position, and one of said blades being slidable with respect to another of said blades from a retracted to an extended position during rotation of said housing.

2. A winding head for winding a gap-type heater comprising a housing, a plurality of winding blades extending from said housing in the same general direction, a wire source, means for rotating said wire source and said housing relative to one another about an axis extending in said general direction for winding wire from said source around at least two of said blades, one of said blades being mounted on said housing for tilting from a winding position to a winding release position, one of said blades being slidable with respect to another of said blades be tween a retracted and extended position, and means for sliding said slidable blade during said winding of said wire for Winding said wire around at least three of said blades.

3. Apparatus for winding a series heater comprising a housing, an elongated blade extending from said housing, a second blade extending from said housing, an extendible blade mounted on said housing, means for biasing said extendible blade to a retracted position, means for rotating said housing about an axis parallel to said elongated blade, said three blades projecting in the same general direction, and means for extending said extendible blade to an extended position with respect to the others of said blades during rotation of said housing.

4. Apparatus for winding a series heater comprising a winding housing, an elongated blade extending from said housing, a second blade extending from said housing, an extensible blade mounted on said housing, means for biasing said extensible blade to a retracted position, means for rotating said housing about an axis parallel to said elongated blade, said blades extending in the same general direction from said housing, means to feed heater wire to said blades whereby heater wire is wound thereon, and means for extending said extensible blade to an extended position with respect to the others of said blades during the winding of said heater wire.

5. Apparatus for winding integral series heaters comprising a rotatable shaft, a housing mounted on said shaft, a plurality of winding blades mounted on said housing, one of said winding blades being both slidably and tiltably mounted on said housing, means for rotating said shaft, means independent of the means for rotating said shaft for tilting said one blade from a tilted position with respect to said shaft to a position parallel to said shaft and means independent of the means for rotating said shaft for sliding said one blade between a retracted and an extended position with respect to the others of said blades during the rotation of said shaft.

6. Apparatus for winding integral series heaters comprising a rotatable shaft, a housing mounted on said rotatable shaft, a plurality of blades fixed to said housing, one of said blades being tiltably mounted on said housing and another of said blades being both tiltably and slidably mounted on said housing, resilient means for tilting said blades to a tilted position with respect to the axis of said shaft, means for tilting said tiltable blades to a parallel position with respect to said axis, means for rotating said shaft and means independent of the rotation of said shaft for sliding said slidable blade between retracted and extended positions with respect to the others of said blades during the rotation of said shaft.

7. Apparatus for winding a series heater comprising a housing, an elongated blade fixed to said housing, a second blade tiltably mounted on said housing for tilting between a tilted position and a position parallel to said elongated blade, a third blade tiltable and slidably mounted on said housing for tilting between a tilted position and a position parallel to said elongated blade and for sliding between a retracted and an extended position, means for resiliently holding said second and third blades in their tilted positions, means for tilting said second and third blades to their parallel position and means for sliding said third blade relative to the others of said blades to its extended position.

8. Apparatus for winding integral series heaters comprising a rotatable shaft, a housing mounted on said shaft, a plurality of winding blades mounted on said housing, one of said blades being both slidably and tiltably mounted on said housing, means for rotating said shaft, means independent of the rotation of said shaft for tilting said one blade from a tilted position with respect to said shaft to a position parallel to said shaft and means independent of the rotation of said shaft for sliding said one blade between a retracted and an extended position with respect to the others of said blades, said means for sliding said one blade comprising a pair of cylindrical coaxially mounted cams having contacting mating teeth, one of said cams being rotatable with respect to the other and means for rotating said rotatable cylindrical cam with respect to the other cylindrical earn.

9. Apparatus for winding a series heater comprising a plurality of at least three blades mounted on a housing, at least one of said blades being tiltable with respect to said housing, at least one of said blades being slidable between a retracted and an extended position with respect to the others of said blades, means for holding at least two of said blades including said tiltabl-e blade parallel to each other, means for holding said slidable blade in its retracted position, means for rotating said housing, means for feeding wire to said housing in a helical manner, and means for extending said slidable blade to its extended position during the rotation of said housing and while feeding wire thereto.

10. A winding head comprising a housing, at least two blades extending from an end of said housing, means for holding said blades in a parallel position, means for moving said blades to a collapsed position with respect to each other, a further blade mounted for sliding on said housing from a retracted position to an extended position with respect to the others of said blades, a wire clamp projecting from said housing and having a clamping portion, the end of said extensible blade in its retracted position being nearer said end of said housing than the clamping portion of said clamp, the end of said extensible blade in its ex' tended position being beyond the clamping portion of said wire clamp and between the end of one of said first two blades and said clamping portion, and means to move the extensible blade between its retracted and its extended position.

11. Means for winding integral series heaters compris ing a rotatable hollow shaft, means for rotating said shaft, a cam slidably mounted in said hollow shaft, a winding head mounted on said rotatable shaft for rotation therewith, said head comprising a housing, a plurality of blades mounted on said housing and projecting therefrom, one of said blades being fixed to said housing in a direction parallel to said shaft, another of said blades being til-tably mounted on said housing, and a further one of said blades being both tiltably and slidably mounted on said housing, resilient means to tilt said tiltable blade in a direction nonparallel with said shaft, means including said sliding cam for tilting said tiltable blades to a direction parallel to said shaft, resilient means for urging said sliding blade to a retracted position and means for sliding said slidable blade to an extended position with respect to the others of said bladesduring rotation of said winding head.

12. A winding head comprising a housing, at least two blades extended from an end of said housing, means for holding said blades in a parallel position, means for moving said blades to a collapsed position with respect to each other, a further blade mounted for sliding on said housing from a retracted position to an extended position, a wire clamp projecting from said housing and having a clamping portion, the end of said extensible blade in its retracted position being nearer said end of saidhousing than the clamping portion of said clamp, the end of said extensible blade in its extended position being beyond the clamping portion of said wire clamp and between the end of one of said first two blades and said clamping portion, means to move the extensible blade between its retracted and its extended position, and means to rotate said head about an axis parallel to one of said blades.

13. A winding head comprising a housing, at least two blades extended from an end of said housing,- means for holding said blades in a parallel position, means for moving said blades to a collapsed position with respect to each other, a further blade mounted for sliding on said housing from a retracted position to an extended position, a wire clamp projecting from said housing and having a clamping portion, the end of said extensible blade in its retracted position being nearer said end of said housing than the clamping portion of said clamp, the end of said extensible blade in its extended position being beyond the clamping portion of said wire clamp and between the end of one of said first two blades and said clamping portion, means to move the extensible blade between its retracted and its extended position, means to rotate said head about an axis parallel to one of said blades, and means to teed wire in' a helical man ner to said winding head.

14-. Apparatus for winding integral series heaters cornpirsing a shaft, means for rotating said shaft, a winding head mounted on said shaft, said head comprising a housing, a plurality of blades mounted on and projecting from said housing, at least one of said blades being tiltablle with respect .to said housing from a position at an angle to said shaft to a position parallel to said shaft, one of said blades being slidably mounted with respect to said housing, a wire holder on said housing and projecting therefrom, said wire holder having a wire hold ing portion, means for holding said slidable blade in such position that the end thereof is between the wire holding portion of said wire holder and said housing, means for tilting said tiltable blade to its parallel position and means to slide said slidable blade to a point where the end thereof extends beyond the end of said wire holding portion but is between the ends of said plurality of blades and the wire holding portion.

15. Apparatus for winding integral series heaters comprising a rotatable shaft, a winding head mounted on said shaft, said head comprising a housing, a plurality other and means for rotating said rotatable cylindrical cam with respect to the other cylindrical cam, said teeth being of truncated right triangular form, the truncated ends of said teeth being in a plane perpendicular to the axis of said cylindrical cams. 7

16. Means for winding integral series heaters comprising a rotatable hollow shaftya carnslidably mounted in said hollow shaft, a winding head mounted on said rotatable shaft, said head comprising a housing, a plu rality of blades'=mounted on salid head and projecting therefrom, one-of said blades being fixed to said housing in a direction parallel to said shaft, another of said blades being tiltably mounted on said housing, and a further one of said blades being both tiltably and slidably mounted on said housing, resilient means to tilt said tiltable blade in a direction non-parallel with said shaft, means including said sliding cam for tilting said tiltable blades to a direction parallel to said shaft, resilient means for urging said sliding blade to a retracted position and means for sliding said slidable blade to an extended position with respect to the others of said blades, said means for sliding said slidable blade comprising a pair of coaxial cylindrical cams having contacting mating teeth, one of said cam-s being fixed and the other of said cams being rotatable about its axis, and means for rotating said rotatable earn independently of the rotation of said rotatable shaft.

17. Apparatus for winding integral series heaters comprising a shaft, means for rotating said shaft, a winding head mounted on said shaft, said winding head comprising a housing, a plurality of blades mounted on and projecting from said housing, at least one of said blades being tiltable with respect to said housing from a posi tion at an angle to said shaft to a position parallel to said shafit, one of said blades being slidably mounted with respect to said housing, a wire holds-non said housing and projecting therefrom, said wire holder having a wine holding portion, means lfor holding said slidable blade in such position that the end thereof is between the wire holding portion of saidwire holder and said housing, means for tilting said ti ltable blade to its parallel position andrneans to slide said slidable blade to a point wherethe end thereof extends beyond the end of said wire holding portion'but is between the ends of said plurality of blades and" the wire holding portion, means to feed wire to said winding head and means to move said wire feeder in a direction parallel to the axis of rotation as said head isirotated, whereby Wire is fed to said blades in a helical manner.

of winding blades mounted on said housing, one of said 7 blades being both slidably and tiltably mounted on said i housing, means for rotating said shaft, means independent of the rotation of said shaft for tilting said one blade from a tilted position with respect to said shaft to a position parallel to said shaft and means independent of the rotation of said shaft for sliding said one blade between a retracted and an extended position with respect to the others of said blades, said means for sliding said one blade comprising a pair of cylindrical coaxdally mounted cams having contacting mating teeth, one of said cams being rotatable with respect to the 18. Apparatus for winding a series heater, including a frame, a winding head assembly rotatably mounted on'said frame and including a housing, an elongated blade extending from one side of said housing, a pair of blades pivotally supported on said housing and movable between a position parallel to said elongated blade and to a tilted position to reduce the spacing between said blades, one .of said til-table blades being slidably mounted, means for biasing said tiltable blades to tilted position and cam means mounted on said frame and movable into said housing for causing'pivotal movement of said pivoted. blades to position parallel to said elongated blade, and means associated with said slidable blade for causing movement of said slidable blade between extended and retracted positions with respect to the others of said blades.

19. Apparatus for winding a series heater, including a frame, a winding head assembly rotatably mounted on said frame and including a housing, elongated blade extending from one side of said housing, a pairof blades pivotally supported on saidhousing and movable between a position-parallel to said elongated blade and to a tilted position to reduce the spacing between said blades, one of said tiltable blades beingslidably mounted, means for biasing said tiltab l-e blades to tilted position and cam means mounted on said frame and movable into said housing for causing pivotal movement of said pivoted blades to position parallel to said elongated blade, and means associated with said siidable blade for causing movement of said slidable blade between extended and retracted positions with respect to the others of said blades, said last means including a cam assembly having one portion fixed to said rfmaime and a second portion motatably and slidabiy mounted on said frame and a cam follower means associated with said slidable blade for causing movement of said slidable blade toward its extended position when said 0am pants are moved relative to each other.

References Cited in the file of this patent UNITED STATES PATENTS FOREIGN PATENTS Switzeriand Dec. 16, 1949 

1. A WINDING HEAD FOR WINDING A GAP-TYPE HEATER COMPRISING A HOUSING, MEANS FOR ROTATING SAID HOUSING, A PLURALITY OF WINDING BLADES MOUNTED ON SAID HOUSING, ONE OF SAID BLADES BEING MOUNTED ON SAID HOUSING FOR TILTING FROM A WINDING POSITION TO A WINDING RELEASE POSITION, AND ONE OF SAID BLADES BEING SLIDABLE WITH RESPECT TO ANOTHER OF SAID BLADES FROM A RETRACTED TO AN EXTENDED POSITION DURING ROTATION OF SAID HOUSING. 